1. Field
One embodiment of the invention relates to an audiovisual (AV) device that transmits or receives a signal such as a video image or audio, for example, to or from an externally connected electronic device. In addition, the present invention relates to an interface system for connecting the above-described AV device in plurality.
2. Description of the Related Art
As is well known, a digital visual interface (DVI) standard is prevalent as a standard for transmitting a digital video image signal. In recent years, a high definition multimedia interface (HDMI) standard has been employed as a digital signal transmission standard that is a further improvement of this DVI standard.
This HDMI standard, for example, includes a variety of stipulations that does not exit in the DVI standard such as the fact that a digital audio signal can be multiplexed and transmitted as audio in a blanking period of a digital video image signal, the fact that a digital video image signal is transmitted in an RGB signal format and can be transmitted in a format of a YCbCr signal or in a format of a YPbPr signal that is of higher quality than that of the YCbCr signal; and the fact that connection can be made via a USB (universal serial bus)-like small sized HDMI connector.
In addition, in the DVI standard or in the HDMI standard, in the case where one electronic device transmits a signal such as a video image or audio to the other electronic device, a transmitting electronic device acquires extended display identification data (EDID) from a receiving electronic device, thereby a signal can be output in a format that conforms to specification of receiving a display that the receiving electronic device has.
Further, in the DVI standard or in the HDMI standard, a plurality of signal output ports are installed on the transmitting electronic device, and the receiving electronic devices are connected to the signal output ports, thereby making it possible for the transmitting electronic devices to transmit an identical signal at the same time or a signal in another signal-converted format to a plurality of receiving electronic devices. In this manner, signal transmission can be achieved such that only a video image can be displayed by means of a receiving first electronic device, and then, only audio is reproduced by means of a second receiving electronic device.
For example, in the case where the HDMI standard has been employed, an optical disk reproducing apparatus that reproduces an optical disk such as a DVD (digital versatile disk) may operate as a transmitting electronic device while (i) and (i) a large screen high definition display and (ii) a 2-channel stereo speaker and an AV (audio video) amplifier, which may include a 5.1-channel audio reproducing function for example, operate as a plurality of receiving electronic devices. A video image with a high image quality is displayed by means of the television image receiver and audio with a high sound quality is reproduced by means of the AV amplifier.
In the meantime, it is necessary to synchronize the display video image by the television image receiver with audio reproduction by the AV amplifier. As a result, in the television image receiver and in the AV amplifier, times required for processing their video image signal and audio signal are recorded as the above-described EDID data.
Thus, an optical disk reproducing apparatus can acquire EDID data from the television image receiver and the AV amplifier, respectively, and can control the display video image and the reproduced audio in synchronism with each other by using the time required for video image signal processing of the television image receiver and the time required for audio signal processing of the AV amplifier.
However, in a current situation, for synchronization control, it is necessary for a user to input and set to which signal output port an electronic device is connected to an optical disk reproducing apparatus that is a transmitting electronic device, to which signal output port an electronic device is connected to display a video image, and to which signal output port an electronic device is connected to reproduce audio, and handling becomes complicated.
In Jpn. Pat. Appln. KOKAI Publication No. 2005-57714, there is disclosed a configuration such that at the time of connecting a plurality of receiver devices to a transmitter device and transmitting video image and audio data that conform to the HDMI standard, video image and audio data are transmitted to a receiver device capable of reproducing video image and audio based on the EDID data acquired from the receiver device; only video image data is transmitted to a receiver device capable of reproducing only video image; and only audio data is transmitted to a receiver device capable of reproducing only audio.
In addition, in Jpn. Pat. Appln. KOKAI Publication No. 2006-19857, there is disclosed a configuration such that a tuner, an image recording/reproducing apparatus, a monitor can be connected to each other in longitudinal manner; a receiver requests specification for a desired video image signal to a video image signal transmitter; and, in the case where the image recording/reproducing apparatus enters a stop mode, a video image signal outputted from the tuner is directly transmitted to the monitor.
Further, in Jpn. Pat. Appln. KOKAI Publication No. 2002-344898, IEEE1394 is disclosed as a standard for interconnecting AV devices, and a DVD player, a TV monitor, and an AV amplifier are connected to each other in accordance with the IEEE standard. In this document, there are described: means for obtaining processing delay information for video image display processing of the TV monitor; and means for an AV amplifier to acquire the information and to adjust audio delay.
Furthermore, in Jpn. Pat. Appln. KOKAI Publication No. 2006-33436, an HDMI standard is disclosed as a standard for interconnecting AV devices; and between a video image monitor and an AV amplifier and between the AV amplifier and a DVD player are connected to each other in accordance with the HDMI standard. Moreover, there are described means for acquiring a delay time for monitor video image display processing and means for delaying an audio signal.